<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            height: 100vh;
            margin: 0;
        }
        #head{
            height: 10%;
            background: #008B8B;
        }
        #body{
            height: 75%;
            background: rebeccapurple;
        }
        #left{
            height: 100%;
            width: 20%;
            background: orange;
            float: left;
        }
        #main{
            height: 100%;
            width: 80%;
            background:gray;
            float: left;
        }
        #foot{
            height: 15%;
            background: rebeccapurple;
        }
    </style>
</head>
<body>
<div id="head">头部份</div>
<div id="body">
    <div id="left">导航部分</div>
    <div id="main">主题内容</div>
</div>
<div id="foot">脚部分</div>
</body>
</html>